Treatment of petroleum products



July 13 1926.

J. C. BLACK E l' AL TREATMENT oF PETROLEUM PRODUCTS Filed June l. 1925711 for@ 0715?),

722:4 rz@ Gaza/.faz

RNE

Patented July 13, 1926.

UNITED STATES 1,592,329 PATENT orrlcr..A

JOHN C. :BLACKl OF DESTREHAN, LOUISIANA, AND WIRT D. RIAL AND RAYMOND'l.

HOWES, F WILMINGTON, CALIFORNIA.

TREATMENT OF PETROLEUM PRODUCTS.

Application led June 1,

Our invention relates to the treatment of hydrocarbons and particularlyof petroleum products indicating a high sulfur content and otherconstituents that form undesirable substances or compounds, one of thechief purposes of our invention being to treat synthetic petroleumproducts with a view to removing all or the highest percentage ofobjectionable substances and one of the objects of our invention beingto provide a method by which crude petroleum products may beeconomically treated for the purpose of refining the same.

Other objects will appear from the following specification 'inconnection with the accompanying drawing which is illustrative ofapparatus for carrying outthe method and in which the view is anelevation, the various pieces of apparatus being shown in theco-ordinated, connected relation in which they function to carry out themethod either by batch or in continuous manner. .i v

This invention relates chiefly to the treatr ment ofthe lighterhydrocarbon products of the petroleum group, eomprehended in the termgasoline, whether of straight run, yielded by ordinary distillationmethods, or of synthetic nature, produced by high temperature andpressure, and hence it will be understood that any7 cracked stock havingthe boiling points of gasoline, or the stock generally known assynthetic naphtha, or ressure distillate, is included in this disc osureand is Within the spirit of the invention. It is recognized that certainstocks or products of crude oil of the lighter grades contain sulfurcompounds, and also constituents which form resinsv and resinous gums.This is particularly true of syn-. .thetic' products falling within theboiling point range'Y required for the stock known as gasoline andproduced by high temperatures andpressure, or merely by hightemperatures or by what is generally termed cracking The productresulting from the decomposition of petroleum oils by high temperatureand pressure or by merely high temperatures in a crude gasoline, and isknown in the art as crude synthetic gasoline, and this invention isdirected chiey l i to the treatment of this crude vsynthetic stock,though other hydrocarbons respond- 6 5 ing to the treatment areobviously inaussuED eluded thereunder, such as crude naphtha or pressuredistillate above-referred to.

Since all syntheticA and some natural stock cont-ain sulfur andconsiderable gums andl gum-forming and other undesirable constituents,it is the object of this invention to remove these compounds orsubstances, and produce from a distillate containing inferior products alfinished gasoline marketable as a first grade'product.

It is a recognized fact that certain gums i925. serial No. 34,024.

- and gum-forming compounds, especially the di-oleines, althoughreacting with sulfuric acid, are not removed by it, as the product ofreaction is oil solubles. These compounds are objectionable in a motorfuel or lamp oil. We have also found that although sulfuric acid andother reagents remove some sulfur, there exists a point beyond which theremoval of sulfur is n0 longer e'fectually removed by these agents.

To eliminate the gum and gum-forming constituents and to reduce the highsulfur contents of low boiling products and especially yof a cracked orsour motor fuel, or lamp oil, to Within the limits generally specifiedfor marketable products and to produce a first grade fuel or'lamp oil,we"

have discovered the present method, the details of which shall nowappear, it being understood that changes in the practice' of the processshall not be a departure from the spirit of after.

We prefer to use for this process a crude synthetic naphtha, although anaphtha may be used that has a longer boiling point the invention asexpressed herein` range, such as` pressure distillate above referred to;the crude gasoline in this speciication we wish to have understood as anunrefined distillate having the proper boiling points for finishedgasoline and resulting from carcking or treatment by high temperature.and pressure. This stock is usually treated with sulfuric acid, forpurposes of removal of some of the undesirable compounds orconstituents. While We prefer to start with said treated synthetic crudegasoline, we would have it understood that our process is not limited tothat practice, andy our -invention consists generally in heating thecrude synthetic naphtha with an alkaline solution, mixing the treatedlow boiling product with heavier hydrocarbons and then distilling themixture, and specifically our invention consists of the steps set outhereinafter, in the sequence in which they occur in an apparatus of thetype show n, in connection with Which the invention will now bedescribed.

Reference is made to the accompanying drawing which shovvsdiagrammatically the apparatus'fvvhiclf'may be used for the processi vBy means of a pump 1, crude synthetic naphtha, treated in theusualmanner With acid, is delivered from pipe line 2 to -pipe line 3 into amixer 4, of ordinary baffled construction, and constitutingsubstantially agitators. This mixer 4 is supplied with once-used,relatively Weak alkaline solution, as caustic soda, through pipe line 5,by means of a pump 6, to which the used alkaline agent is supplied froma tank 7, through line 8. ,Alkaline solution, once used, as explained,is constantly supplied to the tank 7, as will appear presently. themixer 4, a partial neutralization of acid treated gasoline is effectedunder normal temperatures, that is, in the absence of any supplied heat,and such temperature may range from 70 F. to 90 F., or be of that degreeresulting from storage conditions. Complete neutralization of a crackedstock, after heavy acid treatment, Vis 'extremely diflicult in coldstate, and hence the preliminary neutralization is resorted to to renderthe stock more sensitive and' susceptible to the subsequent treatment,hereinafter detailed, and to reduce the acid co-ntent, (Where such acidvtreatment precedes the present treatment), which requires furtherneutralization. Since the alkaline agent does act upon any product inthe oil which reacts acid, it will be understood that the alkalinesolution used herein is not confined to neutra-lizing acids, nor infact,

to the function of neutralization.

From the mixer 4, the mixture of the crude synthetic naphtha andalkaline solutionis passed through pipe line 9, into a settling chamber10, in which the caustic alkali settles out from the hydrocarbons and isdrawn ofi' through pipe 11, into a suitable tank 12.

The stock, being under a pressure above atmospheric and preferably offrom thirty to 100 pounds, then passes through line 13, into a heatexchanger 14, of any known type, in fwyhich some of the heat of incomingtreated hot gasoline, as explained hereinafter, i\absorbed by the cold,crude synthetic naphtha, passing through the exchanger /14, in theexchanger 14, the temperature of the mixture is raised to approximately150 F. and, leaving the exchanger 14, through pipe line 15, enters amixer 16. This mixer 16, is supplied With a large excess of relativelystrong alkaline solution from the supply tank 17, through line 18,

pump 19, and line 20,-and the fresh alkaline 4best results from and'onthe particular distillate undergoing treatment. The heater 22 issupplied through pipe 22 with a heating medium, which is drawn offthrough pipe 22 In our experience, and for the most beneficial effectand advantageous results, We have found that the temperature to whichthe mixture, to Wit, the synthetic naphtha and caustic is subjectedshould preferably not exceed 350 F. is maintained on the of time whichWill enable the alkaline solution to Work uniformly and effectively uponthe naphtha, in its heated condition, and thereby effect a thorough andcomplete neutralization of the stock Where it has been first acidtreated. vWe consider this hot alkaline treatment of the utmostlimportance in obtaining the satisfactory results which our experienceproves, inremoving undesirable compounds and especially sulfur andobjectionable sulfur combinations from the synthetic crude naphtha.,Whether priorly acid treated or not. XVe find also that this hotalkaline action upon the synthetic crude naphtha operates toy eliminatesome of the gum-forming constituents and to affect other gum-formingconstituents in a manner to render them readily removable or extractableby any available means, as explained later. lVe would here have itunderstood again that this hot alkaline solution used herein is notlimited to merely Working a neutralization of an acid treated stock,Vbut performs the other functions mentioned above.

In order to insure the most thorough neutralization of anacidtreatedstock and to reduce to a minimum the sulfur and sulfurv combinations,and also the forming constltuents stock, we pass I gums and gumprevalentin a cracked the mixture through pipe 23 into a mixer 24, and from themixer 24, convey the mixture through pipe 25, through an injector 26disposed in the top of a drum or tank 27. By injection of the mixture inthe drum 27. the contact of the hot alkaline solution with the hotgasoline is as nearly perfect as possible, With the result that themajority of the sulfur and nearly all of the gums and gum-formingconstituents are broken down and are hence readily removable from theproduct, as Will appear later.l i

It will be observed that the mixture of naphthaand alkaline solution, inorder tu have the 'best effects, must bekept in a state The temperatureused mixture for a period l of continuous agitation, and this agitationto prevent vaporization or any substantial vaporization of the heatedsynthetic hydrocarbons, and to executethe process in the I' liquidphase. The heavier portions of the lmixture settle on the bottom of, andare forced out from the tank 29, through pipe 30, into the used'alkalinesolution storage ltanky 7, while the lighter portion, which includes a.mixture of gasoline and a small percentage of the alkaline agent, isforced out of the drum 29, through pipe line 31, into the bottom of theheat exchanger 14, 'and from the top of the heat exchanger 14,

' through line 32, into a cooler From the cooler 33, the mixture isforced through pipe line 34, into a tank 35.a valve 36 being pro-` videdon'the pipe 34, to regulate the pressure'on the system, including thecooler 33, for the purpose of preventing vaporization.

From the tank 35, -whatever small quantity of the heavier solutionremains and precipitates may be drained off through valved pipe 36, totank 37, from which the solution may be returned through line 38, to theused alkali tank 7, for reuse, as explained at the outset.

The'treatment thus far described, of the crude synthetic naphtha withthe caustic alkaline' solution, under the temperature condition named,towit, not exceeding 350 F., and under a pressure above atmospheric andsufficient to prevent vaporization or substantial vaporization, yields aproduct of straw color and good odor, but with the sulfur content notdiminished to a satisfactory low percentage. We have found also thatthis hot treatment of crude synthetic naphtha breaks down thegum-forming or resinous constituents, which are either held in solutionor are cast down after a period of time, as a viscous precipitate,without however removing them. To reduce the sulfur content to thelowest possible minimum, and render the i treated stock gum free, we mixthe treated gasoline with heavier hydrocarbons, preferdrawnbfrom thetank 35, through pipe line Afur content of 110%,

crude synthetic naphtha and the straightrun gasoline are separablyproduced and then mixed together.

To find also that the distillate resulting from the distillation of themixture is substantially free from gum and gum-forming constituentswhich, as explained are extracted by the heavier hydrocarbons, upondistillation with it, after having been rendered extractable by theprocess as outlined.

The distillate obtained, we have found, requires no other treatment thanthat usually applied to the'straight--run stock, and we have found thatthe straight-run or natural gasoline in the crude oil, (if crude oilwere used as the solvent), is much improved by the mixture andsubsequent distillation.

A specific example o f results obtained by our process as' abovedescribed and as being actually practiced by us follows:

The crude synthetic naphtha, having a sulwas first acid treated in theusual manner. The acid treated stock was then subjected to treatmentwith a caustic soda solution according to the method as disclosed inthis specification, reducing the sulfur content to 0.84%.

This treated synthetic naphtha was mixed bined gasoline produced by'subsequent dis tillation was composed of 77.7% straight run gasoline and22.3% synthetic gasoline by volume. The sulfur content of the finishedgasoline was 0.07% and it was practically free from gummy residues.

On the other hand, a mechanical mixture,

in the same proportions as above) consisting of the treated syntheticnaphtha and the straight run gasoline distilled from the crudeindependently, finishes with a sulfur content of 0.22% and is otherwisean undesirable product, containing `a considerable amount of gummyresidue.

What we claim, is:

1. The process of purifying acid treated synthetic or` cracked petroleumproducts having the boiling points of gasoline which consists intreating the products with a relatively weak alkaline solution topartially neutralize the products; in removing the weakalkaline'solution; in mixing with the products thus treated a relativelystrong alkaline solution and subjecting the mixture to a temperature notlexceeding'350o F. while tion to break down the the relatively strongalkaline preventing substantial vaporization of the products, to causethe relatively strong alkaline solution to break down gums and gumforming bodies, in cooling the mixture, in separating the alkalinesolution; in mixing the products with a heavier hydrocarbon, and in thendistilling the mixture to remove the gum and gum forming bodies.

2. -The process of purifying acid treated synthetic or cracked petroleumproducts having the boiling point of gasoline; which consists in treatinthe products-With a relatively Weak alkaline solution in the absence ofany supplied heat to partially neutralize the acid-treated product; inseparating the relatively Weak alkaline solution from` the products; inmixing with t-he products a relatively` strong alkaline solution; insubjecting the 'mixture to a temperature not exceeding 350 F. and tocontinuous agitation to cause the relatively strong alkaline solugumsand gumforming constituent, in maintaining a pressure upon the mixtureto prevent substantial vaporization, in separating the alkaline solutionfrom the products, in mixing with the products a hydrocarbon heavierthan the product treated, and in distilling the mixture to effect theremoval of the gums and gum-forming bodies,

3. The process of purifying unrefined acid treated distillates havingthe proper boiling points for asoline and resulting from cracking, whichconsists in effecting a partial neutralization of the acid treateddistillates With a relatively weak alkaline solution, inthe absence ofany supplied heat; separating from the distillates 'the alkalinesolution, then mixing With distillates a relatively strong alkalinesolution and subjecting thev mixture to a temperature not exceeding 350F. and agitating the mixture oil In 'testimony whereof we have set our`to break down the gums and gum-forming constituents in the distillates,in separating solution from the distillates, cooling the distillates,mixing with the distillates a crude oil containing a from the products4. The process of purifying acid treated products resulting fromcracking which consists in mixing with the products a Weak alkalinesolution and agitating the mixture to effect a partial neutralization ofthe acid treated productsin the absence of any supplied heat.;` inseparating the relatively weak alkaline solution; in mixing thepartially neutralized products with a relatively strong alkali andsubjecting the mixture to Va temperature not exceeding 350 F. and toconstant agitation to break down gums and gum-forming constituents,While preventing substantial vaporization; in separating the relativelystrong alkali 'from the products; in cooling products; in mixing theucts thus treated with crude oil. having a percentage of gasoline,andlin then distilling the mixture to cause the crude oil to remove fromthe treated products, the. gums and gum-forming constituents.

5. The process of purifying acid treated synthetic petroleum productshaving the boiling point of gasoline, which consists .in partiallyneutralizing the acid treated products and separating the neutralizingagent in breaking down Vthe gums and gum-forming constituents inthepetroleum products by a strong alkali under a temperature not exceeding350 F.; in

separating the alkali and the reaction products from the petroleumproducts; and then removing the gums and gum-forming constituents bymixing the productsl thus treated with crude o'il and distillingy themixture l vvhereby the gums are absorbed by the crude hands.

' J OHN C. BLACK.

WIRT D. RIAL.

RAYMOND T. HOWES.

rod-

